Write the equation y squared plus 6 y minus 12 x minus 39 is equal to 0 in standard form.

Start with y² + 6y − 12x − 39 = 0 and group the y terms: y² + 6y = 12x + 39. Complete the square by adding 9 to both sides, since half of 6 is 3 and 3² = 9. This gives (y + 3)² = 12x + 48 = 12(x + 4), which is choice A.

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